U.S. patent number 6,677,547 [Application Number 09/986,703] was granted by the patent office on 2004-01-13 for method and apparatus for classifying and recovering the main components of used batteries.
This patent grant is currently assigned to Mitsubishi Heavy Industries, Ltd.. Invention is credited to Takahiko Hirai, Shiro Honnmura, Takeo Kamimura, Masaaki Kurokawa, Reizou Miyauchi, Tadaaki Tanii, Satoshi Tsuzuki.
United States Patent |
6,677,547 |
Tanii , et al. |
January 13, 2004 |
Method and apparatus for classifying and recovering the main
components of used batteries
Abstract
A method and an apparatus for classifying and recovering the
main components of used batteries, particularly, a method and an
apparatus by which the batteries are conveyed on a conveyor while
an alternating magnetic field of a plurality of frequencies is
applied to each and a detection means detects what sort of induced
magnetic field has resulted from the eddy current induced in the
battery. The orthogonal components in the change of the induced
magnetic field are detected; the relationship between these
orthogonal components and the frequencies are compared with the
database of the same which is previously obtained, and the
batteries are sorted according to their classification and size.
This method can sort large amounts of used batteries continuously.
In this invention, the battery will be drawn down into the
detection region either magnetically or mechanically while the
stable transport of the battery is achieved. The method and
apparatus of the invention enable continuous bulk sorting of
batteries, assure a smooth feed, and improve the accuracy with
which the induced magnetic field generated in the battery is
detected.
Inventors: |
Tanii; Tadaaki (Hyogo-ken,
JP), Tsuzuki; Satoshi (Hyogo-ken, JP),
Honnmura; Shiro (Hyogo-ken, JP), Kamimura; Takeo
(Hyogo-ken, JP), Hirai; Takahiko (Hyogo-ken,
JP), Kurokawa; Masaaki (Hyogo-ken, JP),
Miyauchi; Reizou (Hyogo-ken, JP) |
Assignee: |
Mitsubishi Heavy Industries,
Ltd. (Tokyo, JP)
|
Family
ID: |
26531693 |
Appl.
No.: |
09/986,703 |
Filed: |
November 9, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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456562 |
Dec 8, 1999 |
6337450 |
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Foreign Application Priority Data
|
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|
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Dec 8, 1998 [JP] |
|
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10-348313 |
Aug 20, 1999 [JP] |
|
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11-234671 |
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Current U.S.
Class: |
209/575 |
Current CPC
Class: |
B07C
5/344 (20130101); B07C 5/365 (20130101); H01M
6/52 (20130101); H01M 10/54 (20130101); Y02W
30/84 (20150501) |
Current International
Class: |
B07C
5/34 (20060101); B07C 5/344 (20060101); H01M
10/54 (20060101); H01M 6/00 (20060101); H01M
6/52 (20060101); B07C 005/344 () |
Field of
Search: |
;209/575,573,571
;324/426,158.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Walsh; Donald D. R.
Assistant Examiner: Rodriguez; Joseph C
Attorney, Agent or Firm: Crowell & Moring LLP
Parent Case Text
This application is a division of application Ser. No. 09/456,562,
filed Dec. 8, 1999 now U.S. Pat. No. 6,337,450.
Claims
What is claimed is:
1. A method of sorting continuously conveyed batteries comprising:
applying an alternating magnetic field generated by an alternating
current having a plurality of different frequencies to a battery to
be sorted in order to induce an eddy current in the battery; and
detecting an induced magnetic field created by the eddy current
induced in the battery, wherein the battery is drawn into a
detection region on a tilted conveyor belt by an attraction force
generated by a magnet provided adjacent to said detection region
and by the weight of the battery on the tilted conveyer belt, the
induced magnetic field being detected from beside the lower side of
the tilted conveyer belt.
2. A method of sorting batteries according to claim 1, wherein the
magnet in a U-shaped magnet, and the conveyer belt passes between
poles of the U-shaped magnet.
3. A method of sorting batteries according to claim 1, wherein the
induced magnetic field is detected from beside the conveyer belt,
and the magnet is placed below the detection region so that the
battery will be drawn down into the detection region.
Description
FIELD OF THE INVENTION
This invention concerns a method and an apparatus for classifying
and recovering the main components of used batteries. More
specifically, it concerns a method and an apparatus by which the
batteries are conveyed on a conveyor while an alternating magnetic
field is applied to each. A detection means detects what sort of
induced magnetic field has resulted from the eddy current induced
in the battery and in this way determines what sort of battery it
is. The batteries being conveyed on the conveyor are brought to
within a fixed distance of the detection means, and their travel
path is constrained so as to maintain highly accurate
detection.
BACKGROUND OF THE INVENTION
In order to prevent environmental pollution, make the fullest
possible use of natural resources and aid recycling, it is
desirable to classify used batteries according to their main
components.
Devices have therefore been developed which can be used to classify
used batteries without destroying them. Such apparatus apply an
alternating magnetic field to a used battery to generate an eddy
current. By measuring the magnetic field induced by this eddy
current, one can classify the battery according to its main
components.
However, the exterior of a battery is usually covered with an
ornamental steel jacket which has a tendency to influence the
magnetic characteristics.
In Japanese Patent Publication 6-215802, a design was proposed in
which an alternating magnetic field was applied to the used battery
and a very large magnetostatic field (a quasi-magnetostatic field)
was also applied. The magnetostatic field would magnetically
saturate the steel jacket.
The battery separator proposed in Japanese Patent Publication
6-215802 is characterized by the following features. It has at
least one excitation coil (20), which is connected to three
excitation means (21, 22 and 23) and which generates an alternating
magnetic field; a positioning means to position the battery or
storage battery (10) in the alternating magnetic field; three
detection means (30, 31 and 32), which measure the induction while
the battery or storage battery (10) is in the alternating magnetic
field; and four means (41, 42, 24 and 34) to induce a
quasi-magnetostatic field in the battery whose properties are being
measured via the induction. The quasi-magnetostatic field will
virtually saturate at least a part of the ferromagnetic portion of
the battery or storage battery (10).
The numbers given above are those used in the drawings appended to
Patent Publication 6-215802.
As is explained in the Patent Publication 6-215802, when the jacket
of the battery is magnetically saturated, the magnetic
characteristics of the used battery are no longer influenced by the
jacket, but are now determined by the main components constituting
the battery within the jacket. Thus by measuring the field created
by the eddy current induced by the alternating field, one can
determine what the main components of the battery are.
However, in the prior art technique, when the steel jacket of the
used battery is magnetically saturated, an attraction force is
generated between the jacket and the coil. Thus this method is not
suitable for continuous sorting of batteries.
If the batteries are positioned one by one inside the coil and a
magnetic field is applied to them, the method described above can
be used successfully to sort the batteries by composition. However,
if a very large magnetostatic field is applied while a large number
of batteries are being continuously fed or dropped into the coil,
the batteries will be attracted to the coil when the field is
applied and the feed will be interrupted. This makes continuous
sorting problematical.
When an alternating magnetic field is applied to the used batteries
so that the induced magnetic field which is generated can be
measured, the batteries, which are being conveyed on a belt, must
be prevented from shifting up, down, left or right on the belt.
When they are in position to be detected by the detection means,
the distance between the battery and the detection means must
remain fixed; and the batteries must be transported smoothly,
without getting hung up.
However, because the prior art technique makes use of a saturation
field, the field strength is extremely large. In practical terms,
this means that it is difficult to achieve a smooth movement of the
batteries on the belt.
SUMMARY OF THE INVENTION
In view of the shortcomings of the prior art, the object of this
invention is to enable continuous bulk sorting of batteries, to
assure a smooth feed, and to improve the accuracy with which the
induced magnetic field generated in the battery is detected.
To address the aforementioned shortcomings in the prior art, the
present invention is designed as follows. The method of sorting
batteries according to the invention entails inducing in a battery
being continuously conveyed a weak magnetic field and an
alternating magnetic field containing numerous frequency
components. The induced magnetic field created by the eddy current
induced in the battery is then detected to determine what sort of
battery it is. The strength of the induced magnetic field and the
phase-shift are detected with respect to the alternating field.
Based on the relationship between the classification/the size of
the battery with respect to the strength/the phase-shift of the
induced magnetic field which were previously obtained, the battery
is then sorted according to type and size.
A further refinement of the method of sorting batteries according
to the invention is characterized by the fact that the strength of
the magnetostatic field is between 0.01 T (Teslas) and 0.3 T.
Another embodiment of the method of sorting batteries according to
the invention entails inducing in a battery being continuously
conveyed an alternating magnetic field containing numerous
frequency components. The induced magnetic field created by the
eddy current induced in the battery is then detected to determine
what sort of battery it is. The strength of the induced magnetic
field and the phase-shift are detected with respect to the
alternating field. Based on the relationship between the
classification/the size of the battery with respect to the
strength/the phase-shift of the induced magnetic field which were
previously obtained, the battery is then sorted according to type
and size.
A further development of the foregoing method of sorting batteries
is further characterized by the fact that the relationship between
the type and size of the battery, and the strength and phase of its
induced magnetic field has a tolerance range for every frequency
component of the alternating field. From the set of tolerance
ranges, the type and size of the battery can be determined.
Another refinement of the method of sorting batteries according to
the invention is further distinguished by the fact that the
strength of the magnetostatic field should be set at a level such
that the feed of the batteries is not hindered.
With this invention, an eddy current is generated in batteries
which differ in their main constituents. The induced magnetic field
resulting from this eddy current causes characteristic changes
depending on the materials which constitute the battery. By
detecting these changes, the batteries can be sorted by their main
ingredients.
In particular, if a weak magnetostatic field is superposed on an
alternating field, the differences between the variations in eddy
current which are observed with different sorts of batteries will
be enhanced. Reducing or not applying the magnetostatic field
allows the batteries to be conveyed at high speeds.
Using signals of multiple frequencies allows batteries to be sorted
by composition with greater accuracy. Combining a number of sorting
apparatuses allows batteries to be sorted by composition even
though they may be of different sizes or shapes.
In a preferred embodiment of the invention, the strength of the
magnetostatic field is between 0.01 T (Teslas) and 0.3 T, or 1/10
the field strength in the prior art apparatus. Because the field
strength was so large in the prior art apparatus, stability could
not be maintained in the battery feed. With the weaker field, the
accuracy with which the induced magnetic field can be detected does
not suffer, the frictional resistance of the batteries as they are
transported on the conveyor is reduced, and the batteries can be
moved smoothly.
The invention also includes apparatus for implementing the method
of sorting batteries according to the invention. One embodiment of
apparatus for sorting batteries according to the invention rotates
a disk which is oriented obliquely and a second horizontal disk
surrounding the first on an axis which intersects both disks. The
outer disk is rotated faster than the inner, and the batteries are
inserted at their common center. As the disks rotate, the batteries
are arranged at fixed intervals, and this row of batteries is
conducted via conveyor belt past a device which generates a weak
magnetic field, one which generates an alternating magnetic field,
and one which detects changes in the induced magnetic field. This
device detects changes in the strength and phase of the induced
magnetic field which are due to the composition of the battery for
frequency components in at least two ranges. A signal processing
device applies "AND" and "OR" logical operations to the data which
are detected, and outputs them as a signal corresponding to what
sort of battery each is. This output is used to send each sort of
battery to a specific location.
Another embodiment of apparatus for sorting batteries according to
the invention is characterized by the fact that it lacks the device
for generating a weak magnetic field which is present in the
previously described embodiment.
Another embodiment of apparatus for sorting batteries according to
the invention is characterized by the fact that the conveyor belt
is tilted along the axis of its width, and a device is used which
lines up and conveys the batteries so as to stabilize the position
of each battery as it passes the field generators.
A further embodiment of apparatus for sorting batteries according
to the invention is characterized by the fact that the coil for
inducing an alternating current, which is used as the device to
generate an alternating magnetic field, and the detector coil,
which is used as the device to detect changes in the induced
magnetic field, are both local type coils. One of these coils is
large and the other small. Both are placed on the same shaft. This
arrangement gives the device the capacity to detect the composition
of both large and small batteries.
With the apparatus according to the invention, (1) A rotating
conveyor device feeds the batteries at fixed intervals. This
arrangement prevents the detected signal of the battery from being
disturbed by the noise signal generated by the next battery in
line, thus improving the sorting capacity. (2) The conveyor belt is
tilted. The batteries being conveyed are brought past a fixed
position with respect to the width of the belt. This minimizes
variations of the detection signal, thus improving the sorting
capacity. (3) The local excitation coils are placed either above or
below the conveyor belt. This improves the sensitivity of detection
with respect to flat batteries. (4) The size and shape of the local
coils can be selected to correspond to the type and shape of the
batteries being sorted. This allows a larger amplitude detection
signal to be used, thus improving the sorting capacity. (5) The
coil used to detect changes in the induced magnetic field is placed
orthogonal to the direction of the magnetostatic field. This
enhances the effect of the magnetostatic field operating on the
battery, thus improving the sorting capacity.
The invention also concerns a method for constraining the transport
path of the batteries in order to bring each battery to within a
fixed distance of the detection means.
In one embodiment of the method for sorting batteries according to
the invention, an alternating magnetic field containing a number of
frequency components is applied to a battery being continuously
conveyed on a conveyor belt. The battery is then sorted by
detecting the induced magnetic field resulting from the eddy
current induced in it. This method is characterized by the
following. A magnet is placed near the position in which the
induced magnetic field is detected. The attraction of the magnet
causes the battery on the conveyor belt to be drawn into the
detection region, and the induced magnetic field is detected.
In a further development of the method of sorting batteries
according to the invention the method is further characterized by
the fact that the induced magnetic field is detected from beside
the conveyor belt. The magnet is placed near the detection region
so that the battery will be drawn into that position.
In another further development of the method of sorting batteries
according to the invention the method is further characterized by
the fact that the magnet is a U-shaped magnet. The detection region
and the path of transport of the battery are located between the
poles of this magnet.
Another refinement of the method of sorting batteries according to
the invention is further distinguished by the fact that the induced
magnetic field is detected from beside the conveyor belt. The
magnet is placed in the detection region below the conveyor
belt.
In the embodiments of the invention described above, the battery is
drawn toward the detection means by the attractive force of the
magnet so that it cannot slip forward or back, left or right in the
detection region. The distance between the battery and the
detection means is kept fixed so that the transport of the battery
is stabilized. This arrangement facilitates achievement of high
accuracy of detection.
In one preferred embodiment of the invention, a U-shaped magnet is
used. This makes the magnetic field difficult to interrupt and
contributes to the achievement of a strong field, resulting in more
closely constrained transport of the battery.
In another preferred embodiment of the invention, the magnet is
placed under the conveyor belt. The battery is pulled downward
against the surface of the belt. The coefficient of friction
between the battery and the belt surface is increased, and stable
transport of the battery is achieved.
The invention further relates to apparatus for mechanically
stabilizing the transport of the battery. One embodiment of the
battery sorting apparatus according to the invention has a means
for applying an alternating magnetic field containing a number of
frequency components to the battery being conveyed continuously on
the conveyor belt and a means for detecting the induced magnetic
field created by the eddy current induced in the battery. Near the
detection means are a belt to stabilize the position of the
battery, which is driven by a drive means either to rotate or to
move back and forth, and an elevation means to raise and lower the
belt. A position-stabilizing mechanism uses the belt to force the
battery on the conveyor belt toward the detection means.
Another embodiment of the apparatus for sorting batteries according
to the invention has a means for applying an alternating magnetic
field containing a number of frequency components to the battery
being conveyed continuously on the conveyor belt and a means for
detecting the induced magnetic field created by the eddy current
induced in the battery. This embodiment is distinguished by the
fact that the conveyor belt has ridges at fixed intervals along the
length of its surface. In the vicinity of the detection means, the
battery can engage in one of the depressions formed between each
two ridges.
A further embodiment of the apparatus for sorting batteries
according to the invention has a means for applying an alternating
magnetic field containing a number of frequency components to the
battery being conveyed continuously on the conveyor belt and a
means for detecting the induced magnetic field created by the eddy
current induced in the battery. This embodiment is distinguished by
the fact that the conveyor belt has an undulating surface.
Yet another embodiment of the apparatus for sorting batteries
according to the invention also has a means for applying an
alternating magnetic field containing a number of frequency
components to the battery being conveyed continuously on the
conveyor belt and a means for detecting the induced magnetic field
created by the eddy current induced in the battery. This embodiment
is distinguished by the fact that it has a guide panel near the
detection means, which is above the surface of the conveyor belt,
to guide the battery on the belt toward the detection means.
In the aforedescribed embodiments of the apparatus according to the
invention, a mechanical means is used while the battery is being
conveyed to draw the battery toward the detection means. This
arrangement allows the transport path of the battery to be
constrained without any noise appearing in the signal from the
detection means, a problem which occurs when a magnet is used.
A still further embodiment of the apparatus for sorting batteries
according to the invention likewise has a means for applying an
alternating magnetic field containing a number of frequency
components to the battery being conveyed continuously on the
conveyor belt and a means for detecting the induced magnetic field
created by the eddy current induced in the battery. This embodiment
is distinguished by the fact that it has a magnetic belt adjacent
to the detection means, on which the battery is conveyed. With this
embodiment of the invention, the battery sits on a magnetic belt to
which it adheres magnetically. This prevents incidental motion from
occurring while the induced magnetic field is being detected, thus
assuring stable transport of the battery and maintaining a high
accuracy of detection.
Another embodiment of apparatus for sorting batteries according to
the invention has a means for applying an alternating magnetic
field containing a number of frequency components to the battery
being conveyed continuously on the conveyor belt and a means for
detecting the induced magnetic field created by the eddy current
induced in the battery. At the very start of the conveyor belt,
there is a device to control the spacing of the batteries so as to
assure an equal interval between the batteries being transported on
the belt. This arrangement reduces the likelihood that an adjacent
battery will affect the process when a given battery's induced
magnetic field is detected and so assures a high accuracy of
detection.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a first example of the basic configuration of a
battery-sorting apparatus according to this invention.
FIG. 2 shows a second example of the basic configuration of a
battery-sorting apparatus according to this invention.
FIG. 3 illustrates how a number of sorting apparatuses might be
deployed.
FIG. 4 illustrates a cylindrical excitation coil.
FIG. 5 illustrates a horseshoe-shaped excitation coil.
FIG. 6 illustrates a device which generates a weak magnetostatic
field being located underneath the conveyor.
FIG. 7 depicts an example of a device for generating an alternating
magnetic field.
FIG. 8 depicts another example of a device for generating an
alternating magnetic field.
FIG. 9 illustrates a cylindrical AC excitation coil.
FIG. 10 illustrates the use of local AC excitation coils.
FIG. 11 shows the basic configuration of a device for detecting
changes in the induced magnetic field.
FIG. 12 shows an actual configuration of a device for detecting
changes in the induced magnetic field.
FIG. 13 shows some of the elements in a signal processing
device.
FIG. 14 shows the basic configuration of a signal processing
device.
FIG. 15 is a graph of battery detection output in the absence of a
magnetostatic field.
FIG. 16 is an enlarged graph of portion A in FIG. 15.
FIG. 17 is a graph of the frequency characteristics of size C and
size D batteries in the battery detection output.
FIG. 18 is a graph of the frequency characteristics of size AA
batteries in the battery detection output.
FIG. 19 is a graph of the frequency characteristics in the battery
detection output when a magnetostatic field is applied.
FIG. 20 illustrates the principle used in this battery-sorting
scheme.
FIG. 21 is a plan view of a concrete example of a device for
arranging and transporting the batteries.
FIG. 22 is a cross section of a rotary conveyor.
FIG. 23 shows the arrangement of the conveyor belt.
FIG. 24 illustrates how the conveyor belt is installed.
FIG. 25 shows the configuration of a single unit of a sorting
apparatus.
FIG. 26 shows a concrete example of the overall configuration of a
sorting apparatus.
FIG. 27 illustrates a mechanism for stabilizing the transport of
the batteries.
FIG. 28 shows a first preferred embodiment of a device for
stabilizing the position of the batteries.
FIG. 29 shows a second preferred embodiment of a device for
stabilizing the position of the batteries having a configuration
corresponding to that in FIG. 28.
FIG. 30 shows a third preferred embodiment of a device for
stabilizing the position of the batteries also having a
configuration which corresponds to that in FIG. 28.
FIG. 31 shows a fourth preferred embodiment of a device for
stabilizing the position of the batteries having a configuration
which is viewed from a position at a right angle to the path of the
batteries.
FIG. 32 shows the apparatus of FIG. 31 viewed from arrow Z in FIG.
31.
FIG. 33 is a perspective drawing of a fifth preferred embodiment of
a device for stabilizing the position of the batteries.
FIG. 34 is a cross section taken along line Y--Y in FIG. 33.
FIG. 35 is a side view of the main components in a sixth preferred
embodiment of a device for stabilizing the position of the
batteries.
FIG. 36 is a side n view of the main components in a seventh
preferred embodiment of a device for stabilizing the position of
the batteries.
FIG. 37 is a plan view of the main components in an eighth
preferred embodiment of a device for stabilizing the position of
the batteries.
FIG. 38 shows the main elements of a preferred embodiment of a
control device for arranging the batteries at equal intervals.
DETAILED DESCRIPTION OF PREFERRED EMBODIMETS
In this section a detailed explanation of the invention will be
given with reference to preferred embodiments illustrated in the
drawings. Whenever the shapes, relative positions and other aspects
of the parts described in the embodiments are not clearly defined,
the scope of the invention is not limited only to the parts shown,
which are meant merely for the purpose of illustration.
FIGS. 1 and 2 show the overall configuration of this invention. The
battery-sorting apparatus of this invention comprises a device 10,
which generates a weak magnetostatic field; device 20, which
generates an alternating magnetic field; device 30, which detects
changes in the strength and the biconstituent phases of the induced
magnetic field resulting from the eddy current; signal processor
40; device 60, which arranges and transports the batteries; and
sorter 50.
As can be seen in FIG. 3, the battery sorting apparatus in FIGS. 1
and 2 can be connected as a series of sorting apparatuses A, B and
C. Each of battery sorting apparatuses A, B and C can separate
batteries with a specific composition (alkali, manganese, etc.).
Alternatively, a device could be used which extracted batteries of
a given size (D, C, AA, etc.). Battery sorting apparatuses A, B and
C may be connected in parallel or in series, as needed.
Examples of device 10, the device which generates a weak
magnetostatic field, are shown in FIGS. 4 through 6. The device 10
used to generate a weak magnetostatic field shown in the drawings
comprises an excitation coil for generating the field and a power
supply. The coil for generating the field may be cylindrical,
horseshoe-shaped or of some other shape.
FIG. 4 shows a power supply 12 connected to a cylindrical coil 11
through which battery 1 will pass.
FIG. 5 shows a power supply 15 connected to a horseshoe-shaped coil
comprising a horseshoe-shaped magnetic core 13 around which coil 14
is wound.
FIG. 6 shows a device 10 for generating a weak field which is
placed under conveyor belt 16. In this example, battery 1 is held
against belt 16 by the magnetic field, thus assuring that it will
remain firmly in place. This scheme requires idlers 17 in the
vicinity of the field-generating device.
Thus device 10 generates a weak magnetic field and applies a
magnetostatic field to battery 1. This minimizes the effect of
magnetic changes (relative magnetic permeability) due to metals in
the steel jacket on the battery. It also, as will be discussed
shortly, makes it easier to determine the contents of the
battery.
When batteries 1 which are of the same shape but of different
materials are sorted in experiments, differences in the signal
which corresponded to different sorts of batteries are produced
when the field which is applied in the low-frequency region is at
least 0.01 T (Teslas).
According to this principle of detection, data concerning the
different materials in the battery can theoretically be collected
by using a stronger magnetostatic field and magnetically saturating
the jacket. For this purpose, the magnetostatic field must be at
least 1 T.
However, if a strong magnetostatic field is applied, an extremely
large magnetic force will operate on battery 1. This will make it
difficult to transport the batteries at a rapid speed through the
device which generates the field. For example, if the magnetostatic
field which is applied is 0.07 T or greater, a AA battery will be
attracted, and the belt transport shown in FIG. 6 will become
problematical. With fields of 0.3 T or more, D and C batteries will
experience difficulties in getting through the field. Applying a
weak magnetostatic field, then, will assure that battery 1 can be
transported at a high speed.
If the magnetostatic field is generated by the horseshoe-shaped
coil shown in FIG. 5, the configuration of the conveyor can be
simplified. This scheme can be used to separate batteries of a wide
variety of shapes and sizes.
Device 10 to generate a weak magnetostatic field is not limited to
an electromagnet. A permanent magnet could also be employed for
this purpose.
Examples of device 20, the device used to generate an alternating
magnetic field, are shown in FIGS. 7 and 8.
The generating device 20 shown in FIG. 7 comprises oscillators 21,
22 and 23; mixer 24; amplifier 25; and one or more AC excitation
coils 26.
The generating device 20 shown in FIG. 8 comprises oscillators 21,
22 and 23; electronic switch 27; amplifier 25; and one or more AC
excitation coils 26.
The oscillators 21, 22 and 23 should produce signals at low, medium
and high frequencies, respectively. When the signals from the
oscillators 21, 22 and 23 are mixed by mixer 24, the response speed
will be faster than when they are switched by electronic switch
27.
If a field is applied to batteries of different sizes by the same
AC excitation coil, the efficiency will suffer because of the
distance being increased with smaller batteries. For this reason it
is more effective to use a combination of excitation coils 26 as
shown in FIGS. 7 and 8. For example, one coil might be used for
small batteries and another for large ones.
The AC excitation coils can also be placed under conveyor belt 16
as shown in FIG. 6. Examples of the AC excitation coil 26 are shown
in FIGS. 9 and 10.
FIG. 9 shows a cylindrical AC excitation coil. A coil to generate a
weak magnetostatic field is combined with a coil to detect changes
in the induced magnetic field. Battery 1 is dropped into
cylindrical guide 71 and moved forward. Cylindrical coil 72, which
generates a magnetostatic field, is placed outside guide 71.
Between guide 71 and coil 72 are cylindrical coil 73, which excites
an alternating current, and coil 74, which detects changes in the
induced magnetic field. The generating coil 72 is connected to DC
power supply 75. Excitation coil 73 is connected to the amplifier
25 for the device to generate an alternating magnetic field.
Detector coil 74 is connected to the amplifier 32 for the device to
detect changes in the induced magnetic field which is shown in FIG.
1. Thus while coil 72 applies a relatively weak magnetostatic field
to the battery 1 which drops into guide 71, coil 73 applies an
alternating magnetic field. Coil 74 detects the changes in the
induced magnetic field created by the eddy current induced in
battery 1 by the alternating magnetic field.
FIGS. 10(a) and (b) show local AC excitation coils. The drawings
show them used with devices to generate a weak magnetostatic
field.
As is shown in FIG. 10(a), when battery 1 is brought in on conveyor
belt 81, generator coil 82 for the magnetostatic field is placed so
that its magnetic flux penetrates battery 1 laterally. Local
excitation coils 83, which are excited by an alternating current,
are placed facing the interior of generator coil 82. Thus as
generator coil 82 applies a weak magnetostatic field to the battery
1 being transported on conveyor belt 81, local AC excitation coils
83 can apply an alternating magnetic field to the battery. Detector
coils 84 can then detect the changes in the local field induced in
battery 1 by the eddy current created by the alternating field.
As is shown in FIG. 10(b), generator coil 93, the coil which
generates a magnetostatic field, is wound around horseshoe-shaped
magnet 92, and battery 1 is placed in its gap. Local AC excitation
coil 94 is placed orthogonal to battery 1. Thus as generator coil
93 applies a weak magnetostatic field to the battery 1 being
transported, local AC excitation coil 94 can apply an alternating
magnetic field to the battery 1. Detector coil 95 can then detect
the changes in the local field induced in battery 1 by the eddy
current created by the alternating field.
The magnetic field generated by coil 93 in FIG. 10(b) concentrates
the magnetic flux outside the battery in a location facing local AC
excitation coil 94. As the magnetization increases, the effect of
the eddy current induced in battery 1 will increasingly be
experienced in the battery's interior. With this sort of device 20
to generate an alternating magnetic field, AC excitation coil 26
shown in FIG. 7 can apply a magnetic field which generates an eddy
current in the metals constituting the battery. The phase-shift and
strength of the eddy current which flows in the metals constituting
battery 1 will vary according to the electromagnetic
characteristics of the metals and the AC frequency. If fields of
different frequencies are combined and applied simultaneously, a
variety of data can be obtained at one time. This will improve the
responsiveness and allow the batteries to be conveyed at a high
speed.
In this embodiment, oscillators 21, 22 and 23 apply fields of three
separate frequency components simultaneously. Using a high (over
100 kHz), medium (10 to 40 kHz) and low (0.5 to 2 kHz) frequency
allows us to obtain different detection output at three different
frequencies for every battery. If a number of kinds of detection
signals are obtained, using a combination of these signals will
improve the accuracy with which the batteries are sorted.
Generating an eddy current by using the local AC excitation coils
83 and 94 which are shown in FIG. 10 allows the configuration of
the conveyor to be simplified. If a number of local AC excitation
coils of different shapes and sizes are used either coaxially or
along the path of transport, the device can be used to sort a wide
variety of shapes and sizes of batteries without sacrificing
sorting accuracy.
The basic configuration of device 30 for detecting changes in the
induced magnetic field is shown in FIG. 11. As can be seen in this
drawing, detector 30 comprises coil 31, which detects changes in
the induced magnetic field (hereafter simply called "detecting coil
31"); amplifiers 32a, 32b and 32c; filters 33a, 33b and 33c; and
phase discriminators 34a, 34b and 34c. Detecting coil 31 may
comprise separate coils for small and large batteries, and it may
be placed under the conveyor belt.
Although the apparatus would be functional without filters 33a, 33b
and 33c, it functions more efficiently if they are used. Each
selects one of three frequencies, either high, medium or low, which
correspond to the frequencies of the oscillators in the device to
generate an alternating field.
Phase discriminators 34a, 34b and 34c separate the data in the
signal output by the detecting coil, namely the change in the field
strength (A), and the change in phase (.theta.) into its orthogonal
components of X=A cos .theta., and Y=A sin .theta..
An example of the actual configuration of device 30 to detect
changes in the induced magnetic field is shown in FIG. 12. In this
example, the device also generates an alternating magnetic field.
As can be seen in FIG. 12, the short-wave (10 MHz) signal from
master oscillator circuit 111 is converted to three different
frequencies, fH, fM and fL, by frequency step-down circuits 112a,
112b and 112c. The three frequencies are converted to sine waves by
waveform converters 113a, 113b and 113c. They are mixed by mixer
and power amplifier 114, amplified, and output to the AC excitation
coil (not shown).
The signals detected by detector coil 118 are amplified by
amplifiers 117a, 117b and 117c. They are then separated into
frequencies fH, fM and fL by band pass filters (BPF) 116a, 116b and
116c. Phase discriminators (PSD) 115a, 115b and 115c detect the
orthogonal components with respect to reference signals from
frequency step-down circuits 112a, 112b and 112c for each of
frequencies fH, fM and fL, and output them. In this way detector 30
can detect changes in the induced magnetic field generated by eddy
current in battery 1.
If the excitation coil is excited at different frequencies, the
output from those frequencies can be detected simultaneously. This
improves the responsiveness of the apparatus, and the fact that the
signals are simultaneous makes it possible to simplify the
configuration of the signal processor.
If a local detecting coil of the type shown in FIG. 10(b) is used,
the device will be applicable for separating a wide variety of
sizes and shapes, both flat and round.
If a number of local detecting coils are lined up along the
battery's path, and the output from each detected during operation,
the effect of shifts in the battery's position as it is transported
can be mitigated and the accuracy of sorting improved.
When phase discriminators 34a, 34b and 34c take the orthogonal
components of the output signals, the quantity of data is increased
(including data relating to both phase and strength), and the
accuracy of sorting is improved. In other words, if the orthogonal
components of signals at various frequencies are output
simultaneously, the quantity of data available for sorting the
battery is vastly increased, resulting in more accurate
sorting.
The detecting coil, which can be seen in FIGS. 9 and 10, is mounted
so as to be coaxial with the AC excitation coil. However, a
self-induction coil can be used to achieve the same effect. In this
case, the detecting coil and the AC excitation coil would be a
single entity, and, as is shown in FIG. 13, only one portion of the
circuit configuration would need to be modified.
Signal processor 40, which is shown in FIG. 14, comprises device
41, which generates a reference signal, and AND/OR circuits 42, 43
and 44. AND/OR circuits 42, 43 and 44 perform "AND" and "OR"
operations on the orthogonal component outputs for detection
signals associated with the frequencies fH, fM and fL and the
outputs of reference signal generator unit 41, which outputs
previously determined values for these signals. In this way output
is obtained which discriminates among various types of
batteries.
For example, changes in the detection output for a battery in the
absence of a magnetostatic field are shown in FIGS. 15 and 16. In
both figures, the orthogonal components of the output signal from
the detecting coil for each frequency are plotted as 2-dimensional
coordinates on an X-Y axis. As can be seen in both graphs, the size
and direction of the vector representing the detection signal will
have characteristic values depending on the composition of the
battery (whether it consists of manganese (Mn), alkali (Alk),
nickel-cadmium (NiCd), etc.) and its size (whether it is D, C,
etc.). One can see in the graphs that data associated with the
battery's size are intermingled with data associated with its
composition.
The size and direction of the vector representing the orthogonal
component output depend on the frequency of the alternating field
applied to the battery. When detection signals of appropriate
frequencies are combined and "AND" and "OR" operations are
performed, it becomes possible to sort the battery by its main
components independently of effects from the size of the battery.
The orthogonal outputs for each frequency are plotted as
2-dimensional coordinates on the X-Y axis in FIGS. 17 through 19.
FIG. 17 represents frequency characteristic data for size D and
size C batteries in the absence of a magnetostatic field. FIG. 18
represents data for size AA and size AAA batteries in the absence
of a magnetostatic field. FIG. 19 represents data for size AA and
size AAA batteries in the presence of a magnetostatic field of a
strength of 0.05 T.
The method of discriminating types of batteries by combining
appropriate frequencies is illustrated in FIG. 20 using the example
of how to discriminate an alkaline battery. As is shown in the
graph, if the frequency of the alternating field is 120 kHz, and
there is no magnetostatic field, a D-size alkaline battery will
appear in Zone A, and a C-size alkaline battery will appear in Zone
D. At 40 kHz, a D-size alkaline battery will appear in Zone B, and
a C-size alkaline battery will appear in Zone E. At 2 kHz, a D-size
alkaline battery will appear in Zone C, and a C-size alkaline
battery will appear in Zone F. Thus to sort alkaline batteries
regardless of size, one would select those whose output signals
fell simultaneously into either zone A or D, and either zone E or
B, and either zone C or F. Similar zones can be established for
each composition of battery, and "AND" and "OR" operations can be
used to discriminate whether the signals fall into each of the
zones.
As can be appreciated by the frequency separations in FIGS. 18 and
19, applying a magnetostatic field results in the data points
plotted for the orthogonal component output being more separated
for each type of battery than when the field is not applied. In
other words, applying a magnetic field causes the effects of the
main components of the battery to be expressed strongly. Their
characteristics are separated more clearly, and the battery can be
sorted more readily. For this reason, Zones A through F in FIG. 20
can be smaller when a magnetostatic field is applied than when it
is not. In this embodiment, then, the orthogonal component output
is plotted as 2-dimensional coordinates. Zones are established by
noting where the main components of the battery show up. "AND" and
"OR" operations are performed to determine whether the detected
signal belongs in each zone. In this way the main components of the
battery can be discriminated.
Signal processor 40 is not limited to the unit pictured in FIG. 14.
It could also comprise a multiple-input "AND" circuit, a
multiple-input "OR" circuit, and a circuit to generate a reference
voltage.
Another alternative would be to use multiple A/D devices, a digital
signal processor, and software which could execute the
discrimination protocol described above.
Device 60 for arranging and conveying the batteries may be a
combination of a rotating type and a straight line type conveyor
device. Device 60 could also comprise a control mechanism to space
the batteries at regular intervals as well as a rotating type and a
straight line type conveyor device. If the batteries are arranged
at fixed intervals to be conveyed to the sorting device by a
mechanism to stabilize their positions and thereby prevent the
preceeding or following battery from interfering with the one being
sorted, the accuracy of sorting will improve.
One example of an actual arranging and conveying device 60 to
arrange and convey the batteries is shown in FIG. 21. As can be
seen in the drawing, this arranging and conveying device 60
comprises a rotary-type conveyor device 61 and a straight line-type
conveyor device 62. Rotary conveyor 61 uses centrifugal force to
arrange the batteries 1 which enter the cylinder through inlet 610
and send them to linear conveyor 62. Linear conveyor 62 loads the
arrayed batteries 1 on conveyor belt 81 and carries them forward.
Spacing control device 620 shown in FIG. 38 maintains the batteries
at regular intervals and loads them on conveyor belt 81.
In the course of its travel on conveyor belt 81, which will be
discussed shortly, battery 1 is deposited via one of outlets 65,
which are provided for all types of batteries, between guide walls
64 on either side of conveyor belt 81. As is shown in FIG. 22,
revolving conveyor 61 has an oblique disk 612 and a horizontal disk
614 which surrounds the oblique disk. Disks 612 and 614 rotate on
an axis which passes through both of them. The outer disk, 614,
rotates faster than the inner disk. Disk 612 is rotated by motor
611. Disk 614 is rotated by motor 613, which is on its
periphery.
The battery 1 which enters the conveyor through inlet 610 is loaded
on disk 612, is conveyed to the highest portion of the periphery of
the disk by centrifugal force, and there exits the disk. The
battery 1 which has exited disk 612 is loaded onto the peripheral
surface of outer disk 614. Centrifugal force lines it up against
guide wall 615 as it travels. Batteries 1 are supplied continuously
to spacing control device 620 through outlets 616 provided in guide
wall 615. Spacing control device 620 is rotated by motor 621 as
shown in FIG. 38. It consists of spacing control disk 623, which
has spaces on its periphery into which batteries 1 can fit; linear
guide 624, which supplies batteries 1 to spacing control disk 623;
and circular guide 625, which is on the periphery of spacing
control disk 623. The batteries 1 which are continuously supplied
from rotary conveyor 61 are continuously arranged along the inside
of linear guide 624 and forced onto spacing control disk 623. The
batteries 1 which are forced onto spacing control disk 623 move
into storage space 622, which is along the periphery of the disk.
When, in the course of their rotation, they reach an outlet 626,
the force of a quantity of air blown from air nozzle 627 supplies
them to conveyor belt 81. By varying the rpm of rotary disk 623,
batteries 1 can be supplied to conveyor belt 81 at different
intervals. The use of this spacing scheme will reduce any effect of
adjacent batteries when battery 1 goes past coil 84, the coil which
detects changes in the induced magnetic field. This will improve
the sorting accuracy.
As can be seen in FIG. 23, conveyor belt 81 is operated by drive
motor 66 and a series of pulleys 661. As can be seen in FIG. 24,
conveyor belt 81 is mounted obliquely with respect to a horizontal
surface. This stabilizes the position of battery 1 along the width
of conveyor belt 81 as it is conveyed.
Sorting device 50 may comprise a number of air nozzles, buckets,
and electromagnetic solenoids. It may alternatively comprise a
number of sorting arms and an electromagnetic solenoid. As can be
seen in FIG. 25, a single unit of sorting device 50 is an element
consisting of proximity sensor 51 and electromagnetic valve 52. The
entire apparatus would comprise a number of devices which
corresponds to the number of types of batteries to be sorted.
Proximity sensor 51 detects the passage of the battery being
transported on conveyor belt 81. When it receives a signal which
indicates what type of battery this is, based on the output of
proximity sensor 51 and processing executed by signal processor 40,
electromagnetic valve 52 directs several high-speed air streams at
battery 1. Thus when a battery 1 being transported by conveyor belt
81 is detected by proximity sensor 51 and electromagnetic valve 52
is actuated to expel several high-speed jets of air, the battery is
forced off the conveyor belt, sent to the exterior via outlet 65,
and supplied to a bin. In this case, while battery 1 is moving, the
signal from proximity sensor 51 and the output of signal processor
40 are not simultaneous. Thus the time lag must be corrected by
timing adjustor 53 so as to adjust the actuation of valve 52
properly.
An example of an actual battery sorting apparatus which uses a
number of the above-described elements is shown in FIG. 26. As can
be seen in the drawing, the batteries 1 to be sorted are loaded
onto linear conveyor 62 via inlet 610. The batteries 1 transported
by linear conveyor 62 travel on conveyor belt 81, which is operated
by drive motor 66. They are brought past AC excitation coil 83,
which comprises generator coil 82, comprising weak magnetostatic
field generating device 10 to generate a weak magnetic field, and
alternating magnetic field generating device 20, which generates an
alternating magnetic field. They also go past detector coil 84,
which comprises induced magnetic field change detecting device 30
to detect changes in the induced magnetic field.
Coil 82, which generates a weak magnetic field, is connected to DC
power supply 75. Coil 83, which generates an AC magnetic field, is
connected to amplifier 25. Coil 84, which detects changes in the
induced magnetic field, is connected to amplifier 32. The signal
indicating that the battery has been detected is input into signal
processing device 40.
Signal processing device 40 outputs a signal corresponding to what
sort of battery this is to timing adjuster 53. The signals from
proximity sensors 51, which are mounted at each outlet through
which a given sort of battery will exit, are also input into timing
adjuster 53. These signals are used to actuate electromagnetic
valves 52 and send the battery through the appropriate outlet.
As discussed above, at the same time that coil 82 applies a weak
field to the battery, coil 83 applies an alternating field. Coil 84
detects the field induced by the eddy current generated in the
battery. If at this time battery 1 should shift in any direction as
it is being transported on conveyor belt 81, the distance between
it and the detector coil 84 would change, and the accuracy of
detection would suffer. It is thus essential that battery 1 not
shift about as it is being transported on conveyor belt 81, and
that its position be stabilized. As can be seen in FIG. 27, the
surface 811 of conveyor belt 81 is tilted at a fixed angle u with
respect to horizontal surface 121. However, with this sort of
apparatus, the vibration of conveyor belt 81 is liable to cause
battery 1 to shift up and down or sideways, as shown by the dotted
lines in FIG. 2. This makes it impossible to achieve positional
stability.
FIG. 28 shows a preferred embodiment of a device for stabilizing
the position of the battery. The device is viewed from a position
at a right angle to the direction of transport. In the drawing, 1
is the battery transported on conveyor belt 81, which has a guide
wall 64 on either side. 83 is the coil (hereafter called the
"generator coil") which generates a local alternating magnetic
field and applies it to the battery 1. 84 is the coil (hereafter
called the "detector coil") for detecting the induced magnetic
field generated in and around battery 1 when the alternating field
is applied. These coils are placed against the outer surface of the
guide wall 64. The surface 811 of conveyor belt 81 is tilted at a
fixed angle u with respect to horizontal surface 121. 123 is a
magnet which is placed on the outer side of the detector coil 84 so
that it can exert magnetic force on the battery 1. A number of such
magnets 123 may be placed along the length of conveyor belt 81,
mainly opposite the detector coil 84, or a single magnet may extend
over a given length. The magnet 123 may be a permanent magnet, or
it may be an electromagnet.
In this embodiment, the battery 1 being transported on conveyor
belt 81 is on a surface 811 which is tilted as described above.
This tilt causes the battery to go to the lowest portion of the
surface 811. The magnetic force of magnet 123, which is beyond
detector coil 84, pulls the battery toward the detector coil. Thus
when battery 1 is in the position where it can be detected by the
detector coil 84, the magnet 23 will pull it toward the coil. This
scheme maintains a fixed distance between the detector coil 84 and
battery 1 and thus insures a high accuracy of detection.
FIG. 29 shows another preferred embodiment of a device for
stabilizing the position of the battery. It is viewed from the same
perspective as the embodiment in FIG. 28. In this embodiment, a
U-shaped magnet 124 is disposed so that one of its poles 241 is
just beyond the detector coil 84. In the magnetic gap between poles
241 and 242 of the magnet 124 are conveyor belt 81, which is used
to convey the battery 1; the generator coil 83; and detector coil
84. The magnet 124 may be a permanent magnet or an electromagnet.
Other aspects of this configuration are identical to those of the
embodiment shown in FIG. 28. Identical components have been given
the same reference numbers as in FIG. 28.
In this embodiment, conveyor belt 81 and the battery 1 being
transported on the belt 81 are placed in the magnetic gap between
poles 241 and 242 of U-shaped magnet 124. When battery 1 travels
through the magnetic gap, the magnetic force of pole 241 will draw
it toward the detector coil 84. In this embodiment, the use of a
U-shaped magnet 124 makes it more difficult for the field to be
interrupted. A strong field is achieved, and battery 1 is reliably
drawn close to detector coil 84.
FIG. 30 shows a third preferred embodiment of a device for
stabilizing the position of the battery. In this embodiment, magnet
123 is placed under conveyor belt 81, which is tilted just as in
the previous embodiments. The magnet is placed next to the
undersurface 812 of the belt on its lower side. The magnet 123 may
be a permanent magnet or an electromagnet. Other aspects of this
configuration are identical to those of the first embodiment, and
have been given the same reference numbers. In this embodiment,
magnet 123 is placed under conveyor belt 81 on its lower side. This
means that the attractive force of the magnet 123 draws battery 1
to surface 811 of conveyor belt 81. In the vicinity of the magnet
123, battery 1 will experience much less slippage on surface 811.
The frictional coefficient between the battery 1 and conveyor belt
81 is increased. Battery 1 moves in a stable fashion and is
reliably drawn close to detector coil 84.
FIGS. 31 and 32 show a fourth preferred embodiment of a device for
stabilizing the position of the battery. FIG. 31 is viewed from a
location at a right angle to the direction in which the battery
travels. FIG. 32 is a view of the device in FIG. 31 from the
direction of arrow Z. In this embodiment, a magnet is not used as
in the foregoing three embodiments. Instead, battery 1 is brought
closer to detector coil 84 mechanically.
In FIGS. 31 and 32, 131 is a position-stabilizing belt. It is
mounted in the shape of a triangle on a drive roller 133 and two
idler rollers 134. 132 is a drive motor. Its output shaft is
connected to the drive roller 133. When the drive motor 132 rotates
drive roller 133, the position-stabilizing belt 131 is conveyed
around the three rollers 133 and 134. The drive motor 132, drive
roller 133, the two idle rollers 134 and the position-stabilizing
mechanism mounted on these rollers are all mounted on elevator 135.
When the elevator 135 moves up and down as shown by the arrow in
the drawing, its stabilizing belt 131 exerts pressure on the
exterior of battery 1. Thus the position-stabilizing mechanism 100,
as shown in FIG. 31, has a position-stabilizing belt 131, which is
tilted so as to push battery 1 simultaneously toward that portion
of surface 811 of conveyor belt 81 which is closest to the detector
coil 84 and toward the lower interior surface of guide wall 64. The
guide wall 64 is shaped like an angular letter "U", of which the
flat bottom forms floor 641. The conveyor belt 81 runs on the floor
641. In this embodiment, as drive motor 132 is operating belt 131,
elevator 135 lowers it as shown by the arrow in FIG. 32. When the
lower surface of the position-stabilizing belt 131 presses against
the exterior of battery 1, the battery 1 is pushed by a fixed
pressure toward the lower interior surface of guide wall 64 and
toward that portion of surface 811 of conveyor belt 81 which is
closest to the detector coil 84. In this way the battery 1 is
always brought close to the detector coil 84, and its position is
stabilized.
Unlike the preceeding three embodiments, in this embodiment no
magnet is used. Instead, battery 1 is brought close to detector
coil 84 mechanically. This eliminates the noise which interferes
with the detection signal from detector coil 84 when a magnet is
used, thus allowing a high accuracy of detection to be
maintained.
FIGS. 33 and 34 show a fifth preferred embodiment of a device for
stabilizing the position of the battery. FIG. 33 is a perspective
drawing, and FIG. 34 is a cross section taken along line Y--Y in
FIG. 33. In this embodiment, a so-called "trough" conveyor belt 81
has projections or ribs 141 at fixed intervals along its length. In
FIGS. 33 and 34, the upper surface of the belt 81 has projections
141 at regular intervals, and the projections go all the way across
the belt. The spacing or pitch of the projections 141 is such that
a battery 1 can be loaded between two projections 141 so that it
cannot move at all along the length of the belt.
Between the projections 141 are angled surfaces 142. The portion of
each angled surface at the base of the projections 141 which is
closer to the detector coil 84 is lower, and the portion which is
opposite the coil is higher. This causes battery 1 to move to the
lower portion of the slanted surface 142, where it is closer to the
detector coil 84. In this way, a battery 1 being transported on
conveyor belt 81 will always go to the lower portion of the slanted
surface 142 between the projections 141. In other words, it will
always fall into a position quite close to detector coil 84.
FIG. 35 is a rough side view of a sixth preferred embodiment of a
device for stabilizing the position of the battery. This embodiment
is a modified version of the fifth embodiment. Conveyor belt 151
has a wavy surface with valleys 152 in which batteries 1 can fit.
The detector coil is placed below one of the valleys 152. With this
design, the battery 1 on conveyor belt 151 is above detector coil
84 and inevitably approaches quite near the detector coil 84.
FIG. 36 is a side view of a seventh preferred embodiment of a
device for stabilizing the position of the battery. In this
embodiment, belt 161 has magnetic powder glued to its surface.
Battery 1 is loaded onto the magnetic belt 161 and transported. In
FIG. 36, 161 is the belt on which a coating of magnetic powder has
been glued. When the two belt wheels 162 rotate, the belt moves.
The detector coil 84 is placed near the side of the magnetic belt
161. 163 is the air shooter belt placed upstream from the magnetic
belt 161; 164 is the ordinary rubber belt downstream from the
magnetic belt 161 which expels the battery. In this embodiment, the
battery 1 which is transported from air shooter 163 by magnetic
belt 161 is temporarily fixed to the belt 161 by its magnetic
force. When it has passed close by detector coil 84 and its induced
magnetic field has been detected, it is expelled on rubber belt
164. In this embodiment, battery 1 faces detector coil 84 while it
is temporarily held on magnetic belt 161. Thus the battery 1 is
completely prevented from moving in any way relative to magnetic
belt 161 when its induced magnetic field is detected. This scheme
achieves a high accuracy of detection.
FIG. 37 is a plan view of the essential parts of an eighth
preferred embodiment of a device for stabilizing the position of
the battery. In this embodiment there is an oblique guide panel 171
on the surface of conveyor belt 81. Detector coil 84 is placed on
the side of the conveyor where the path is narrowed by the guide
panel 171. In FIG. 37, the guide panel 171 is formed by removing a
portion of guide wall 64 on conveyor belt 81. Battery 1 is guided
by interior wall 172 to a position facing detector coil 84. The
portion of the path in front of the detector coil 84 is gradually
contracted so that it becomes more narrow. In this embodiment,
battery 1 is mechanically guided by guide panel 171 so that it
arrives in a reliable fashion at a location near detector coil 84.
This scheme uses a simple configuration to achieve a stable
transport and positioning of the battery.
FIG. 38 illustrates a preferred embodiment of a spacing control
device for spacing the batteries at equal intervals. In this
embodiment, batteries 1 are continuously expelled from outlet 616
of the rotary conveyor and travel along until they are stopped by
rotary control disk 623 inside linear guide 624. Rotary control
disk 623 has a space 622 on its periphery in which a single battery
will fit. When the disk rotates, the battery in space 622 moves
toward conveyor belt 81. When this battery 1 reaches outlet 626,
which is on a portion of round guide 625, a jet of air blown out of
air nozzle 627 loads it onto conveyor belt 81. By setting an
appropriate speed for the rotation of rotary control disk 623, the
spacing between batteries 1 on conveyor belt 81 can be kept fixed
at an appropriate value.
EFFECTS OF THE INVENTION
As is discussed above, the basic invention comprises a method of
sorting batteries in which a weak magnetostatic field and an
alternating magnetic field containing numerous frequency components
are applied to a continuously conveyed battery. The induced
magnetic field created by the eddy current induced in the battery
is then detected. The strength of the induced magnetic field and
the orthogonal components of its phase are measured with respect to
the alternating field. Based on the relationship between the type
and size of the battery with respect to the orthogonal components
which were previously obtained, the battery is then sorted
according to type and size. In this way all types of batteries can
be sorted according to size and principal components without
applying a saturation field to the battery.
With the preferred embodiment in which the magnetostatic filed is
between 0.01 T and 0.3 T, the strength of the magnetostatic field
is reduced to 1/10 that used in the prior art. This reduces the
resistance of the battery on the conveyor and allows it to be
transported smoothly without reducing the accuracy with which the
induced magnetic field can be detected.
The invention also includes an embodiment comprising a method for
sorting batteries in which an alternating magnetic field containing
numerous frequency components is applied to a continuously conveyed
battery. The induced magnetic field created by the eddy current
induced in the battery is then detected. The strength of the
induced magnetic field and the orthogonal components of its phase
are measured with respect to the alternating field. Based on the
relationship between the type and size of the battery with respect
to the orthogonal components which were previously obtained, the
battery is then sorted according to type and size. This method
enables the device for generating a weak magnetic field to be
omitted.
With the embodiment of the inventive method in which the
relationship between the classification and size of the battery and
the measured parameters comprises a plurality of measured tolerance
ranges, the relationship between the type and size of the battery
and the strength and phase of its induced magnetic field has a
fixed tolerance range for every frequency of the alternating field.
By combining the tolerance ranges and making a judgment, the type
and size of the battery can be determined.
With the embodiment of the invention in which the magnetostatic
field is applied at a level low enough not to hinder the feed of
the batteries, the transport of the batteries is not interfered
with. Thus the batteries can be conveyed at a high speed.
With the basic apparatus of the invention, an obliquely oriented
first disk and a horizontal second disk surrounding the first are
rotated on an axis which intersects both disks. The outer disk is
rotated faster than the inner disk. Each battery is inserted into
the disks, which results in the batteries being lined up with fixed
intervals between them. This row of batteries is conducted via a
conveyor belt past a device which generates an alternating magnetic
field, and one which detects changes in the induced magnetic field.
This device detects changes in the strength and phase of the
induced magnetic field which are due to the composition of the
battery for at least three sorts of frequency components. A signal
processing device performs "AND" and "OR" operations on the data
which are detected, and outputs them as a signal corresponding to
what sort of battery this is. This output is used to send each sort
of battery to a specific location. This method embodiment utilizes
a simplified apparatus.
With the apparatus which is further developed to include a device
which generates a weak magnetic field past which the batteries are
conducted, all types of batteries can be sorted according to size
and principal components without applying a saturating field to the
battery.
With the embodiment of the apparatus according to the invention in
which the conveyor belt is tilted in the direction of its width and
a device is used which lines up the batteries, the batteries are
stabilized in position as they pass the coil. This improves the
accuracy with which the batteries are sorted.
With the embodiment of the invention in which the alternating
magnetic field generator and the induced magnetic field detector
are each provided with a plurality of coils, the coil used as the
device to generate an alternating magnetic field and the coil used
as the device to detect changes in the induced magnetic field are
the sort of coil which induces a local field. Thus a larger and a
smaller coil can be arranged on the same shaft and used together to
detect larger and smaller batteries. This improves the accuracy
with which the apparatus can sort batteries of different sizes.
With the embodiments of the inventive method in which the battery
is drawn toward the detection means by magnetic force when it
reaches the proper position, it is assured that the distance
between the battery and the detection means will remain constant,
thus allowing the passage of the battery to be stabilized. This
scheme maintains a high accuracy of detection.
If the apparatus is configured with a U-shaped magnet and the
conveyor belt passes between the poles of the magnet, it is less
likely for the magnetic field to be interrupted and a stronger
field is achieved. The passage of the battery thus is further
stabilized.
If the apparatus is configured so that the induced magnetic field
is detected from beside the conveyor belt and and the magnet is
placed below the conveyor, the battery is drawn toward the conveyor
surface. This increases the frictional coefficient between the
battery and the surface of the conveyor, thus further stabilizing
the passage of the battery.
With the embodiments of apparatus according to the invention
provided with a position stabilizing mechanism or a conveyor belt
with a plurality of ridges and intervening depressions or an
undulating conveyor belt surface or a guide panel adjacent the
detecting means, the battery is brought closer to the detection
means by a mechanical device. This eliminates the problem of noise
getting into the signal from the detection means which occurs when
a magnet is used. It also stabilizes the transport of the
battery.
With the embodiment of the apparatus according to the invention in
which the battery is carried on a magnetic belt, the battery is
attracted toward the belt surface. This prevents any relative
movement as the induced magnetic field is detected. It thus
stabilizes the transport of the battery and maintains a high
accuracy of detection.
With the apparatus embodiment of the invention provided with a
spacing control device comprising a battery storage feeder and a
spacing control disk, the batteries are transported on the conveyor
belt with fixed intervals between them. The signal for each battery
can be detected without being affected by adjacent batteries, so
the accuracy of sorting is improved. The foregoing description and
examples have been set forth merely to illustrate the invention and
are not intended to be limiting. Since modifications of the
described embodiments incorporating the spirit and substance of the
invention may occur to persons skilled in the art, the invention
should be construed broadly to include all variations falling
within the scope of the appended claims and equivalents
thereof.
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